Elevator short-circuit & ground-fault protection

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cppoly

Senior Member
Location
New York
For sizing an elevator circuit breaker, the NEC says to size it according to article 430 which uses the full load current (FLC) motor tables.

What if the elevator motor nameplate full load amps (FLA) is larger (by about 10 A) than the table FLC?

Usually the table FLC is larger than the nameplate FLA.
 

JDBrown

Senior Member
Location
California
No time to search for a Code reference at the moment, but I've always been told you have to use the larger of the two. Even if it's not in the Code, it's still a good idea.
 

hbendillo

Senior Member
Location
South carolina
Ideally we size for the nameplate rating but the NEC gives us a guideline for when that is not available. We try and review shop drawings for all our electric motor operated equipment to make sure we got it right. Most of the time elevator shop drawings will give the rating and the recommended circuit breaker size. I find it less than the NEC motor table most of the time but if not, got to go with actual rating. Check the elevator literature to see if it gives a recommended circuit breaker size.
 

cppoly

Senior Member
Location
New York
In 430.6 it says:

Motors built for low speeds (less than 1200 RPM) or high torques may have higher full-load currents, and multispeed motors will have full-load current varying with speed, in which case the nameplate current ratings shall be used.

It should just say if the nameplate current exceeds the table values, the nameplate value should be used. Because now I'm looking on the cut sheet of the motor and I can't find the RPM or high torque listed.
 
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